643edo: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
{{ | {{ED intro}} | ||
== Theory == | == Theory == | ||
643edo is [[consistency|distinctly consistent]] to the [[21-odd-limit]], with a generally flat tendency, but the [[5/1|5th harmonic]] is only 0.000439 cents sharp as the denominator of a convergent to log<sub>2</sub>5, after [[146edo|146]] and before [[4004edo|4004]]. | 643edo is [[consistency|distinctly consistent]] to the [[21-odd-limit]], with a generally flat tendency, but the [[5/1|5th harmonic]] is only 0.000439 cents sharp as the denominator of a convergent to log<sub>2</sub>5, after [[146edo|146]] and before [[4004edo|4004]]. As an equal temperament, it [[tempering out|tempers out]] [[32805/32768]] in the 5-limit and [[2401/2400]] in the 7-limit, so that it [[support]]s the [[sesquiquartififths]] temperament. In the 11-limit it tempers out [[3025/3024]] and 151263/151250; in the 13-limit [[1001/1000]], [[1716/1715]] and [[4225/4224]]; in the 17-limit [[1089/1088]], [[1701/1700]], [[2431/2430]] and [[2601/2600]]; and in the 19-limit 1331/1330, [[1521/1520]], [[1729/1728]], 2376/2375 and 2926/2925. It provides the [[optimal patent val]] for the rank-3 13-limit [[vili]] temperament. | ||
=== Prime harmonics === | === Prime harmonics === | ||
{{Harmonics in equal|643 | {{Harmonics in equal|643}} | ||
=== Subsets and supersets === | === Subsets and supersets === | ||
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== Regular temperament properties == | == Regular temperament properties == | ||
{ | {| class="wikitable center-4 center-5 center-6" | ||
|- | |||
! rowspan="2" | [[Subgroup]] | |||
! rowspan="2" | [[Comma list]] | |||
! rowspan="2" | [[Mapping]] | |||
! rowspan="2" | Optimal<br />8ve stretch (¢) | |||
! colspan="2" | Tuning error | |||
|- | |||
! [[TE error|Absolute]] (¢) | |||
! [[TE simple badness|Relative]] (%) | |||
|- | |- | ||
| 2.3 | | 2.3 | ||
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| 0.0801 | | 0.0801 | ||
| 4.29 | | 4.29 | ||
|} | |||
=== Rank-2 temperaments === | === Rank-2 temperaments === | ||
{ | {| class="wikitable center-all left-5" | ||
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | |||
|- | |||
! Periods<br />per 8ve | |||
! Generator* | |||
! Cents* | |||
! Associated<br />ratio* | |||
! Temperaments | |||
|- | |- | ||
| 1 | | 1 | ||
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| 498.29 | | 498.29 | ||
| 4/3 | | 4/3 | ||
| [[Helmholtz]] | | [[Helmholtz (temperament)|Helmholtz]] | ||
|} | |||
<nowiki />* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct | |||
== Music == | |||
; [[Francium]] | |||
* "Bobson Dugnutt" from ''Don't Give Your Kids These Names!'' (2025) − [https://open.spotify.com/track/1ROUQlzxJR7pDpM8GLujol Spotify] | [https://francium223.bandcamp.com/track/bobson-dugnutt Bandcamp] | [https://www.youtube.com/watch?v=Bg2w1__AW4k YouTube] − in Botolphic, 643edo tuning | |||
[[Category:Sesquiquartififths]] | [[Category:Sesquiquartififths]] | ||
[[Category:Vili]] | [[Category:Vili]] |
Latest revision as of 02:30, 17 April 2025
← 642edo | 643edo | 644edo → |
643 equal divisions of the octave (abbreviated 643edo or 643ed2), also called 643-tone equal temperament (643tet) or 643 equal temperament (643et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 643 equal parts of about 1.87 ¢ each. Each step represents a frequency ratio of 21/643, or the 643rd root of 2.
Theory
643edo is distinctly consistent to the 21-odd-limit, with a generally flat tendency, but the 5th harmonic is only 0.000439 cents sharp as the denominator of a convergent to log25, after 146 and before 4004. As an equal temperament, it tempers out 32805/32768 in the 5-limit and 2401/2400 in the 7-limit, so that it supports the sesquiquartififths temperament. In the 11-limit it tempers out 3025/3024 and 151263/151250; in the 13-limit 1001/1000, 1716/1715 and 4225/4224; in the 17-limit 1089/1088, 1701/1700, 2431/2430 and 2601/2600; and in the 19-limit 1331/1330, 1521/1520, 1729/1728, 2376/2375 and 2926/2925. It provides the optimal patent val for the rank-3 13-limit vili temperament.
Prime harmonics
Harmonic | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | +0.000 | -0.244 | +0.000 | -0.241 | -0.774 | -0.714 | -0.445 | -0.779 | +0.653 | +0.594 | +0.843 |
Relative (%) | +0.0 | -13.1 | +0.0 | -12.9 | -41.5 | -38.3 | -23.9 | -41.7 | +35.0 | +31.8 | +45.2 | |
Steps (reduced) |
643 (0) |
1019 (376) |
1493 (207) |
1805 (519) |
2224 (295) |
2379 (450) |
2628 (56) |
2731 (159) |
2909 (337) |
3124 (552) |
3186 (614) |
Subsets and supersets
643edo is the 117th prime edo.
Regular temperament properties
Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
---|---|---|---|---|---|
Absolute (¢) | Relative (%) | ||||
2.3 | [-1019 643⟩ | [⟨643 1019]] | +0.0771 | 0.0771 | 4.13 |
2.3.5 | 32805/32768, [1 99 -68⟩ | [⟨643 1019 1493]] | +0.0513 | 0.7270 | 3.90 |
2.3.5.7 | 2401/2400, 32805/32768, [9 21 -17 -1⟩ | [⟨643 1019 1493 1805]] | +0.0600 | 0.0647 | 3.47 |
2.3.5.7.11 | 2401/2400, 3025/3024, 32805/32768, 391314/390625 | [⟨643 1019 1493 1805 2224]] | +0.0927 | 0.0874 | 4.68 |
2.3.5.7.11.13 | 1001/1000, 1716/1715, 3025/3024, 4225/4224, 32805/32768 | [⟨643 1019 1493 1805 2224 2379]] | +0.1094 | 0.0881 | 4.72 |
2.3.5.7.11.13.17 | 1001/1000, 1089/1088, 1701/1700, 1716/1715, 2601/2600, 4225/4224 | [⟨643 1019 1493 1805 2224 2379 2628]] | +0.1094 | 0.0816 | 4.37 |
2.3.5.7.11.13.17.19 | 1001/1000, 1089/1088, 1521/1520, 1701/1700, 1716/1715, 1729/1728, 2601/2600 | [⟨643 1019 1493 1805 2224 2379 2628 2731]] | +0.1186 | 0.0801 | 4.29 |
Rank-2 temperaments
Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
---|---|---|---|---|
1 | 94\643 | 175.43 | 448/405 | Sesquiquartififths |
1 | 267\643 | 498.29 | 4/3 | Helmholtz |
* Octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if distinct